package main.java.cn.touna.jss.modules.third.gzt.util;

import cn.touna.jss.common.util.Base64;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import javax.crypto.Cipher;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.IvParameterSpec;
import java.security.Key;
import java.security.spec.AlgorithmParameterSpec;


public class GztDes2Util {
    public static final String ALGORITHM_DES = "DES/CBC/PKCS5Padding";
    private static final Logger logger = LogManager.getLogger(GztDes2Util.class);

    /**
     * DES算法，加密
     *
     * @param data 待加密字符串
     * @param key  加密私钥，长度不能够小于8位
     * @return 加密后的字节数组，一般结合Base64编码使用
     * @throws Exception 异常
     */
    public static String encode(String key, String data) throws Exception {
        return encode(key, data.getBytes("GB18030"));
    }

    /**
     * DES算法，加密
     *
     * @param data 待加密字符串
     * @param key  加密私钥，长度不能够小于8位
     * @return 加密后的字节数组，一般结合Base64编码使用
     * @throws Exception 异常
     */
    public static String encode(String key, byte[] data) throws Exception {
        DESKeySpec dks = new DESKeySpec(key.getBytes());
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
        //key的长度不能够小于8位字节
        Key secretKey = keyFactory.generateSecret(dks);
        Cipher cipher = Cipher.getInstance(ALGORITHM_DES);
        IvParameterSpec iv = new IvParameterSpec("12345678".getBytes());
        AlgorithmParameterSpec paramSpec = iv;
        cipher.init(Cipher.ENCRYPT_MODE, secretKey, paramSpec);
        byte[] bytes = cipher.doFinal(data);
        return Base64.encode(bytes);
    }

    /**
     * DES算法，解密
     *
     * @param data 待解密字符串
     * @param key  解密私钥，长度不能够小于8位
     * @return 解密后的字节数组
     * @throws Exception 异常
     */
    public static byte[] decode(String key, byte[] data) throws Exception {
        DESKeySpec dks = new DESKeySpec(key.getBytes());
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
        //key的长度不能够小于8位字节
        Key secretKey = keyFactory.generateSecret(dks);
        Cipher cipher = Cipher.getInstance(ALGORITHM_DES);
        IvParameterSpec iv = new IvParameterSpec("12345678".getBytes());
        AlgorithmParameterSpec paramSpec = iv;
        cipher.init(Cipher.DECRYPT_MODE, secretKey, paramSpec);
        return cipher.doFinal(data);
    }

    /**
     * 获取编码后的值
     *
     * @param key
     * @param data
     * @return
     * @throws Exception
     */
    public static String decodeValue(String key, String data) throws Exception {
        byte[] datas = decode(key, Base64.decode(data));
        return new String(datas, "GB18030");
    }
}
